1. Field of the Invention
The present invention relates to a water-based ink for ink-jet recording and an ink cartridge.
2. Description of the Related Art
In general, it is demanded for a water-based ink for ink-jet recording that the hue is satisfactory and the durability or stoutness is excellent against light, heat, and ozone. A water-based ink which uses a specific dye has been suggested as the water-based ink for ink-jet recording in which the hue is satisfactory and the durability or stoutness is excellent. See, for example, Japanese Patent Application Laid-open No. 2011-111611 (corresponding to United States Patent Application Publication No. US 2011/0128333).
However, some types of the specific dye as described above tend to cause the change in the easiness of diffusion into a recording medium depending on change in an environmental condition under which the specific dye is used, as compared with general dyes. For example, the humidity affects the easiness of diffusion of the specific dye into the recording medium. For this reason, in a case that a water-based ink containing the specific dye is used to perform ink jet recording, then there is caused such a problem that the optical density (OD value) is lowered in some cases.
In view of the above, an object of the present teaching is to provide a water-based ink for ink-jet recording which provides a satisfactory hue, which is excellent in the durability or stoutness against light, heat, and ozone, and which makes it possible to suppress the lowering of optical density (OD value) in a high humidity environment.